Abstract: Twentieth century urbanization has left a tremendous footprint on the globe. It is generally speaking a spread out fragmented suburban and exurban landscape continuously growing according to what has been called sprawl-like development, increasing energy and automobile dependency, challenging urban sustainability. Recently urban growth has also turned inwards because of economic and political change. Thus one of the main challenges for future urban design will be to ‘compact sprawl’. This thesis, set in the field of urban morphology, explores the spatial conditions for suburban densification by looking at administrative and user-related measures of density, public open space, and pedestrian accessibility. If we consider useful open space, it would not decrease density, but rather increase spatial compactness. So would also a well-connected street network, if we consider accessibility as part of density. The thesis’ first four papers explore new measures that contradict ordinary notions of density and the last three papers examine densification scenarios on different urban scales in collaboration with urban planners in practice.The paper Place syntax explores a possibility to combine the space syntax description of cognitive accessibility, axial line distance, with place attraction into a combined attraction-accessibility analysis model. Empirical investigation shows that place syntax analysis captures pedestrian movement and can be used for new types of location density analyses.Sociotope mapping describes the theoretical body of a new urban planning tool called the “sociotope map” (sociotopkarta) developed in Stockholm planning practice. The map emphasizes that the same public open space can have different direct use values for different people and thereby assesses qualitative open space area.Exploring Ambiterritory investigates the notion of (sub)urban no-man’s-land. Densification most often means increased open space use, which naturally leads to an increase of potential conflicting territorial interests. However, the reduction of vague user space and unclear legal territories by densification can increase the size of useful open space.More green space in a denser city investigates whether little public green space means low accessibility. User questionnaires and GIS-analyses in ten city districts in Stockholm correlate and show that it is possible to have more accessible green space in a denser city.Strategic exurban landscape densification investigates different municipal location strategies and development rates in the municipality of Kungälv. Results show that location strategies create the biggest landscape impact and not development rates.Greening metropolitan growth analyzes the density landscape in Stockholm county region and finds some correlations with health and socioeconomic variables. Growth scenarios in the regional plan for 2030 show decreasing compactness and spaciousness in inner suburbia.Compact sprawl experiments use the measures developed in the former papers on four densification scenarios in two suburbs in Stockholm. The results show how it is possible to efficiently compact modernist sprawl, particularly the inner suburbs.It is likely that we will be more dependent on walking, bicycling, and public transportation in the future. Street networks and public open spaces are then key issues today just as they were at the end of the nineteenthcentury, creating compact, sustainable, liveable, equitable, and more competitive cities. In fact, many compact urban cores such as in Stockholm, London, and Manhattan have through the 20th century persistently stood up to the competition against more sprawling cities. The thesis shows that compacting inner suburbia seems to be the new frontier many cities and planners are facing. In fact, this is a vast unexplored field that needs further attention in urban studies and urban morphology in particular.